The railroads are losing many doors off of box cars in switch yards, due to faulty hasps or latches or due to not latching the doors. The need has been expressed, for self-latching door hasps. Also, a need has been expressed for an intermediate height hasp which is not readily accessible to a thief operating from ground level.
A need also exists for a lock usable with swinging or overhead doors which may be locked while the door is open. When the door is slammed shut the spring-biased bolt latches it closed.